The CPU (Central Processing Unit), is the chip in the computer that actually performs the operations and calculations that are done as a program runs. It is essentially what executes a program.

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How to find which machines are idle on a cluster of many nodes

I run measurements on a cluster consisting of 32 nodes/machines. I do not require all nodes, only 4, for example. The problem is most of the time, the nodes are busy with other people running their ...
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525 views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...
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219 views

CPU or RAM better in old machine?

I'm planning to use one of two old computers as a low-volume backup server. The machine will be online and files will be backed up over ssh/rsync. I will do a minimal install of Ubuntu or Debian ...
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Are “kernel mode” and “user mode” hardware features or software features?

I read that there are two modes called “kernel mode” and “user mode” to handle execution of processes. (Understanding the Linux Kernel, 3rd Edition.) Is that a hardware switch (kernel/user) that is ...
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Kondemand process consumes most of my CPU

Following is the output from top: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3551 mysql 20 0 10.0g 84m 4052 S 9.4 0.1 544:39.87 mysqld 2311 root 20 0 0 ...
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Linux and CPU usage

What does it mean for a core to run at different loads in different moments? How does a 10% load differ from a 90% load? How is this number calculated, essentially?
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diabling cpu cores on quad core processor on linux

I want to disable 3 CPU cores and run my processor on a single core. I have used command:maxcpus=1. But after this I executed this command ls /sys/devices/system/cpu. It still shows ...
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1k views

How can I start a process using cpulimit?

I am trying to use cpulimit for testing an app I'm developing under low resource conditions, and I need the process to start under the influence of cpulimit. It is not sufficient to start the program ...
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kswapd0 takes 99% to 100% CPU in RHEL 6.3

I have 5 systems on which I have just installed RHEL6. System configuration is CPU-i7 HDD-500 GB RAM-2 GB Swap- 4 GB I have installed the same software's and all the configuration as per ...
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129 views

How to know number of cores of a system in Linux?

I wanted to find out how many cores my system has. So I searched the same question in google. i got some command like: $ lscpu command. When i tried this command, it gave me the following result: In ...
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288 views

AIX CPU usage - how to know how many CPUs running?

Over AIX 6.1 - I do see the following output, it says I have 16 Max Physical CPUs; but there are only 8 active - why is that? The system will use the remaining 8 if needed? Or are they disabled? # ...
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310 views

Run linux process at very very low priority?

I have regular process that not so important but will consume so much CPU power, and I have another process which is really important, but it spend most of the time idle, but when it got a job it ...
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194 views

why is my laptop-mode configuration being ignored?

I am running Debian GNU/Linux Jessie (testing) on my laptop. I enabled the systemd laptop-mode service: $ sudo laptop_mode Laptop mode enabled, active [unchanged] and in my ...
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2answers
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Does BIOS read directly the bootloader or load it into RAM?

I'm trying to understand the very first steps of the boot process. The CPU read the BIOS It reads a fixed address instruction It will jump to the first BIOS instructions address It will execute ...
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Kernel not detecting multicore cpu

Kernel Version 3.3.4-5.fc17.x86_64 CPU info: sashan@dhcp-au-122 ~ $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) ...
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Which “Processor family” to choose under “Processor type and features”?

I have recently compiled a minimal kernel for my Intel(R) Pentium(R) Dual CPU T3400 @ 2.16GHz, and chose CONFIG_MCORE2 (Core 2/newer Xeon) under "Processor type and features > Processor family" I ...
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1answer
32 views

Threads vs interrupts

What does it mean when threads are time-sliced? Does that mean they work as interrupts, don't exit while routine is not finished? Or it executes one instruction from one thread then one instruction ...
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1answer
39 views

Identify machine configuration via code

I am writing a program where I need to know about the machine configuration. Code will run on Linux. I want to find the following: Number of CPU Cores Number of CPU Sockets Number of Disks If it's ...
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215 views

Why does a linux guest consume 100% of the host CPU under VirtualBox when the guest appears idle?

I am using VirtualBox on a Macbook Pro running Yosemite. My linux guests sometimes consume 100% of the host CPU (viewed in Activity Monitor) even though the guest is idle. Why is the host CPU ...
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91 views

Does it take time for process to utilize CPU?

I have a single-core x86 machine where I execute the burnP6(from cpuburn package) for 1 second and then kill the program: while true; do /usr/bin/burnP6 & sleep 1; pkill burnP6; sleep 1; done ...
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179 views

/proc/cpuinfo shows a single core under VirtualBox

My host machine is Windows 7, running an Intel Core i5 Processor. The Task Manager shows that I have 4 boxes under the Performance tab, which I assume to be 4 cores. However on my OEL guest (on ...
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117 views

Find average CPU, vMem, sMem usage on 1, 5, and 15min

I am trying to find at time T the average CPU usage on 1, 5, and 15min, just like what you get from /proc/loadavg Same thing for virtual memory, and swap memory. I would be fine with a python ...
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826 views

Setting running process affinity with taskset fails

I'm attempting to limit a process to a given number of CPU cores. According to the taskset man page and this documentation, the following should work: [fedora@dfarrell-opendaylight-cbench-devel ~]$ ...
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Why my cpu spend so much time on system? [closed]

top - 08:58:42 up 20 days, 8:23, 1 user, load average: 67.17, 58.94, 62.75 Tasks: 630 total, 40 running, 524 sleeping, 0 stopped, 66 zombie Cpu(s): 57.3%us, 41.6%sy, 0.0%ni, 0.0%id, 0.0%wa, ...
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Top c - CPU usage >200% Will it Crash?

I would appreciate some advice from your experience. My main concern is I really REALLY do not want to cause the computer server to crash. The question is, I am running a program on a Linux computer ...
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1answer
262 views

Make effective the changes in CPU governor plugin

I'm using Debian Testing + Xfce. I added to my panel the plugin the handle the CPU governor. My problem is that the setting that I do on the plugin interface are not made effective. Maybe because I'm ...
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521 views

Process priority and cpu speed

In some devices the cpu speed is dynamic, being faster when there is more load. I was wondering if it is possible to set nice level or priority of a process so that it does not influence an increase ...
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1answer
465 views

Queries about top command

top command shows the process cpu utilization, and it when we sum the cpu utilization of all the processes then it goes greater than 100%. And how can it shows the cpu utilization of each process( ...
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Why is the range of load average not 0-1+ for all cpu's together?

I know that load average is 0-1(or 0-1024) per cpu. E.g a busy quad-core can have a load average of 4.0 or higher. (e.g if there are many tasks). I understand it can be huge like 100+ etc. I also ...
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1answer
56 views

Get list of supported opcodes

Is there a way to get a list of supported opcodes for a given architecture? Such as a listing in /proc similar to /proc/cpuinfo.
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1answer
67 views

What does the term 'Unix Processor' mean?

I have Googled around and found a few references to this term, but nothing which defines what it actually means. Does anyone here have experience with such a device? What features must a processor ...
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1answer
57 views

Plot values returned by command output

I have a little script that prints the CPU temperature after each T period of time, so the output is something like this: 19/02/15,01:00 30 19/02/15,02:00 33 19/02/15,03:00 38 19/02/15,04:00 32 ...
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66 views

Is there a way to change the number of processors a program sees?

Is there any way I can trick a program into thinking the system has fewer processors? To explain: I am debugging a program that creates as many threads as it has processors, using ...
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1answer
278 views

How to calculate per CPU load

Is there any C API to calculate per CPU load? /proc/loadavg gives the CPU average load for all available CPUs and /proc/stat doesn't mention anything about active processes per CPU. How can I obtain ...
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2answers
700 views

What does % utilization mean in htop if only 1 process can execute at a time?

I see that the htop command reports respective the % of utilisation of each CPU core and also that of the processes. We know that only 1 process can execute at a time in the CPU. How is it possible ...
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1answer
201 views

Check SSE3 support from bash?

Is there a way to check whether or not the current system supports SSE3 from a bash script? I'm currently writing an installer script, and the program in question has an alternate version that takes ...
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1answer
135 views

CPU and RAM monitorization by parent id

I'm trying to monitor the CPU and RAM usage (in % of total for example) of a given process wich may spawn several processes. The parent process is /bin/rscw so I get its pid by ppid_bl=$(ps -ef | ...
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1answer
275 views

When speaking about cache size of a CPU, we only need the size of the cache at the furthest level [closed]

When speaking about cache size of a CPU, do we only need to know the size of the cache at the furthest level (such as at level 3, when the cache hierachy is 3-level)? Instead of the sum of all the ...
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1answer
541 views

How to increase the system CPU load/utilization in Solaris 10 to test nagios?

I want to increase the system CPU load in Solaris 10 in order to test this scenario in Nagios. I'm running following command to get the CPU utitlization in Solaris: bash-3.00# sar -s 10 60 SunOS ...
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1answer
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Running a Snow Leopard 10.6.7 Image on an AMD: The CPU has been disabled by the guest operating system

I am quite frustrated so I have turned to this medium in hoping to get an answer. After reading thousands of forums and trying out various methods (I have lost track what I have tried already) I still ...
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1answer
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How to increase Xen guest CPU utilization?

My Xen dom0 is a Gentoo x64 pvops. I boot my guest Gentoo, in PV mode, system with the same kernel my dom0 uses. When I emerge in the guest system, building a CPP package, I am experiencing low CPU ...
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1answer
862 views

Overclocking software for Linux?

Is most overclocking done strictly at the BIOS level, or is there a way to do it from a running operating system? And if so, is there a way to do it from Linux? I'm running Ubuntu presently and am ...
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how practical the number of cores in Android

I've often wondered how practical the cores usage in Android smartphone. I'm asking here because Android is based on Linux. I'm looking from technical perspective. The articles that I've read so far ...
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1answer
41 views

Show CPU core usage for parent process and its child processes

Is it possible to display CPU core usage just for a single process and its child processes on Linux?
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1answer
95 views

How to ensure ssh via cgroups on centos?

When some cpu-intensive processes are running on the server, chances are that we could not log in to this machine with error 'operation timeout' via ssh command. According to this post answered by ...
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How to reduce temperature of my Toshiba with Slackware?

I have a Notebook Toshiba with Slackware 14.1 64bits $ lspci: 00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09) 00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 ...
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CPU always at 80°C while the system is idle

My system is quite unused at the moment: %Cpu(s): 10.3 us, 3.1 sy, 0.0 ni, 85.9 id, 0.7 wa, 0.0 hi, 0.0 si, 0.0 s but still the temps sensors give me are quite high: acpitz-virtual-0 ...
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Distributing CPU cores between cgroups and outside world

Is it possible to manage access to CPU cores in a similar fashion that memory limiting works? In particular I need to be able to dynamically create and destroy cgroups that will limit a particular ...
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1answer
65 views

cpulimit on a bash script which runs other commands

I have a bash script which runs other cpu-intensive commands . When I apply cpulimit on the bash script, the output of top shows processes for the commands inside the script still run without ...
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Is it safe to disable Frequency Scaling and CPU idle Power Management support for Real Time purposes?

I'm using a Raspberry Pi board and I would like to build a real time system. During the kernel configuration, I found the CONFIG_CPU_FREQ option, which (from the help section) allows you to change ...